Process of making dialkylbarbituric acid.



STATES ,PA IAIEN I ()FFTCE.

JULIUS AL'ISCHUL, OF BERLIN, GERMANY, ASSIG-NOR TO AU IICN (nrlCS-ELL SCHAFT FUR ANILIN FABRIKATION, OF BER-LIN, (JrIGRMANY.

Specification of Letters Patent.

Patented Sept. 5, 1905.

Application filed January 10,1905. Serial No. 240,504.

in which formula alk means alkyl radicals. I have found that these compounds can be prepared with a very good yield by condensing dialkylmalonamids with neutral alkyl others of carbonic acid according to the following general equation:

Alk.()

00: Alk.O

dialk ylearbonate.

Nilt:

Alk 00. NH:

dialkylmalonaiuhl.

Alk (JONH ZAllLOHdo co Alk ooNH alcohol. dialkylbal'bituric acid,

The condensation is produced by heating the above starting products in the presence of suitable alkaline condensing agents such as, for instance, alkali alcoholates with or without the addition of a suitable solvent. As the condensation is carried out in the presence of an alkaline condensing agent, there is formed an alkali salt of dialkylbarbituric acid, from which the free dialkylbarbituric acid is obtained by the action of a suitable acid.

In order to carry out my invention, I proceed, for instance, as follows, the parts being by weight: Three parts of diethylmalonamid EHQLUXUQNHQQ are mixed with three parts of sodium ethylate and three parts of diethyl carbonate, and the mixture is heated for several hours in a vessel provided with a reflux condenser. The alcohol formed is then distilled off, the remaining dry residue is dissolved in cold water, the solution liltered off from small quantities of unaltered amid, and the diethylbarbituric acid then precipitated by addition of hydrochloric acid to the filtrate. By recrystallization from water the acid is at once obtained in a chemically-pa re state, showing the melting-point of lJl centb grade.

The above-given proportions of the ingredients used can be varied within wide limits. It was, however, found advantageous in order to obtain good yields to use for one molecular proportion of diethylmalonamid more than one molecular proportion of ethyl carbonate and more than two molecular proportions of sodium ethylate. Instead of em1.)loying sodium ethylate in the dry state the condensation can also be produced by using a solution of sodium ethylate in ethyl alcohol, the process as for the rest being carried out in the same manner as above described. The process proceeds likewise in an analogous manner it instead of diethylmalonamid other dialkylmalonamids or instead of sodium ethylate other alkali alcoholatcs or other suitable alkaline condensing agents or if instead of diethyl carbonate other dialkyl carbonates are used.

Having now described my invention and in what manner the same is to be performed, what I claim as new is 1. The process of preparing dialkylbarbituric acids having the above given general formula which process consists in condensing dial kylmalonamids with dialkyl carbonates in the presence of suitable alkaline condensing agents and isolating from the resulting product the free dialkylbarbituric acid, substantially as hereinbefore described.

2. The process of preparing diethylbarbituric acid which process consists in condensing diethylmalonamid (UJI Ifi)2U-(C().NI'I2)2 with dialkyl carbonate in the presence of suitable alkaline condensing agents and isolating from the resulting product the free dicthylbarbituric acid, substantially as hcreinbefore described.

3. The process for the production of d1- ethylbarbituric acid Which process consists in my name, this 16th day of December, 1904, in heating diethylmalonamids With sodium the presence of two subscribing Witnesses. ethylate and diethyl carbonate and isolating from the resulting product the free diethyl- JULIUS ALTSCHUL' 5 barbituric acid, substantially as hereinbefore Witnesses:

described. HENRY HASPER,

In Witness whereof I have hereunto signed VVOLDEMAR HAUPT. 

